Fill in the blanks with appropriate modals:

He……………….. not buy a car.

need

The correct modal to fill in the blank is need not.

The modal need not is used to express that something is not necessary. In this case, the speaker is saying that the person does not need to buy a car because they can use public transportation or walk.

The other options are incorrect.

• Has to is used to express obligation. In this case, the person does not have to buy a car, but they might.
• Needs is also used to express necessity, but it is more forceful than need not.
• Need is used to express necessity, but it is not as forceful as needs.